Selectively disabling add-ins revealed that the SharePoint Portal Server client PowerPoint add-in was causing the problem(PKMOfficeAddIn.PwrPntUI.1). I disabled the add-in by setting LoadBehavior to zero in the following registry key:

Selectively disabling add-ins revealed that the SharePoint Portal Server client PowerPoint add-in was causing the problem(PKMOfficeAddIn.PwrPntUI.1). I disabled the add-in by setting LoadBehavior to zero in the following registry key: